The metabolism of [14C]beta-carotene and the presence of other carotenoids in rats and monkeys.
The metabolism of beta-carotene has been studied in both rats and Rhesus monkeys, following the oral administration of [14C]beta-carotene in olive oil supplemented with 1 mg/mL alpha-tocopherol. In the rats, peak serum accumulation of [14C]retinol occurred 4 h after a single oral dose, but we were not able to detect [14C]beta-carotene in rat sera at any time up to 72 h after dosing. Small amounts of [14C]beta-carotene were found in the livers, although 88-94% of the recovered radioactivity was localized in the retinol fraction after saponification. Although radioactivity was also found in fractions other than beta-carotene and retinol, the amounts were too small to allow characterization. In the monkeys, peak accumulation of [14C]retinol in serum occurred between 8 and 24 h after supplementation. Some [14C]beta-carotene was also present. Most of the absorbed radioactivity was stored in the liver as [14C]retinol, although 2-8% was present as [14C]beta-carotene. Other organs also contained [14C]beta-carotene, confirming the ability of the monkey to absorb intact beta-carotene. In addition, monkey livers and other organs were found to contain lutein, zeaxanthin, alpha-cryptoxanthin, beta-cryptoxanthin and beta-carotene, presumably arising from dietary sources.
Krinsky
N I
NI
Department of Biochemistry, Tufts University School of Medicine, Boston, MA 02111.
Mathews-Roth
M M
MM
Welankiwar
S
S
Sehgal
P K
PK
Lausen
N C
NC
Russett
M
M
D000042:Absorption; D000818:Animals; D002338:Carotenoids / Q000008:administration & dosage / Q000032:analysis* / Q000097:blood / Q000378:metabolism*; D004032:Diet; D005260:Female; D008099:Liver / Q000378:metabolism; D008253:Macaca mulatta; D009928:Organ Specificity; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors; D014801:Vitamin A / Q000097:blood; D014807:Vitamin D / Q000008:administration & dosage; D019207:beta Carotene
D019207:beta Carotene; D014801:Vitamin A; D014807:Vitamin D; D002338:Carotenoids